Rotating attachment for extruding apparatus



June 23, 1964 H. KUSCH ROTATING ATTACHMENT FOR EXTRUDING APPARATUS 3Sheets-Sheet 1 Filed Jan. 5, 1962 Jnvenfar:

Horst K U S C H ttorney June 23, 1964 H. KuscH ROTATING ATTACHMENT FOREXTRUDING APPARATUS 3 Sheets-Sheet 2 Filed Jan. 5, 1962 Jnvemar:

Horst K U20 H Attorney June 23, 1964 H. KUSCH 3,137,895

ROTATING ATTACHMENT FOR EXTRUDING APPARATUS Filed Jan. 3, 1962 5Sheets-Sheet 5 Jnvenfor:

orst K S C H Att y United States Patent 2 C 3,137,895 ROTATINGATTACHMENT FOR EXTRUDING APPARATUS Horst Kusch, Osnabruck, Germany,assignor to A. Hagedorn & Co., Aktiengesellschaft, Osnabruck, Germany, acorporation of Germany Filed Jan. 3, 1962, Ser. No. 164,011 Claimspriority, application Germany Sept. 25, 1961 Claims. (Cl. 18-12) Myinvention relates to a spinning device and more particularly to spinningnozzles adapted to be attached to extruding apparatus in the manufactureof ribbons, foils, sheets or the like from highly viscous thermoplasticand heat sensitive synthetic materials such as polyvinylchloride.

Known extrusion nozzles of said type comprise a cylindrical or conicalspinning chamber provided with an elongated slot longitudinallyextending in the chamber wall substantially in the direction of the axisof the chamber. The synthetic material to be processed is introducedunder pressure by an extruding apparatus into said chamber to passtherethrough substantially in axial direction thereof and it emergeslaterally from said chamber through said slot in the desired shape, suchas a ribbon, foil, sheet or the like. These known spinning nozzles havethe disadvantage that the material leaves the chamber of the nozzle in acompletely uncontrolled manner causing substantial portions of materialto remain in the chamber longer than others, this resulting indecompositions of unduly long retained material particularly if heatsensitive material is processed.

In the attempt to avoid said disadvantage it has been suggested to placein the nozzle chamber a rotatably mounted worm to supply spinning massto the spinning slot. This provision, however, not only did noteliminate said disadvantage but added other disadvantages. The worm,which imparts to the mass in the nozzle chamber primarily a motion inits axial direction and increases the pressure within the chamber doesnot directly influence and particularly not accelerate a uniform exit ofthe mass through the spinning slot and thus the worm will rotate withinthe compressed mass in the spinning chamber causing strong adiabaticheating up of the mass and thus decompositions thereof. For this reasonit has been suggested to substitute the said worm by a true mixing orstirring device extending along the spinning slot, such mixing devicesubstantially consisting of mixing blades or pins radially extendingtothe wall of the spinning chamber from a rotatable shaft mounted in andcoaxially with the spinning chamber.

However, even the aforesaid device was not fully satisfactory becausethe mixing blades or pins reaching to the wall of the spinning chamberobstructed the forward movement of the mass within the spinning chamberand this proved particularly damaging when long nozzles were used.Furthermore, spinning mass settled on the stirring blades or pins,particularly at their bases, requiring frequent cleaning of the nozzle.

It is an object of my invention to avoid the said and otherdisadvantages and to provide a spinning device, more particularly anextrusion nozzle for the manufacture of ribbons, foils, sheets or thelike from highly viscous, heat sensitive thermoplastic syntheticmaterials such as polyvinylchloride, which will assure a continuous anduniform and smooth passage of the spinning mass through the elongatedand narrow spinning slot.

According to my invention, particularly when the same is applied to theprocessing of heat sensitive thermoplastic synthetic spinning masseswhich does not need an additional substantial plasticizing andhomogenization within the spinning chamber, I place centrally into thespinning chamber a rotatably mounted mandrel or winding rod around whichthe spinning mass, introduced under pressure into the spinning chamber,winds in helically superimposed layers and, when passing the spinningslot penetrates therethrough under the pressure prevailing in thechamber. The said mandrel or winding rod may have a smooth, or a fullyor partially rifled or serrated surface, it may have either asubstantially uniform circular, oval, triangular, polygonal or othercross section, and such cross sections may vary throughout the length ofthe mandrel or winding rod which possibly may be provided with aplurality of regularly arranged, substantially radially extending shortprojections such as pins or horns which do not reach the inner surfaceof the chamber.

The spinning chamber within the nozzle may be in known mannercylindrical and/or conical and may be provided with more than onespinning slot. The spinning mass may be introduced into the spinningchamber at or near one or at or near both ends thereof. The said mandrelor winding rod may be driven directly by, or form an extension of theworm of the extruder feeding the spinning chamber, or it may be drivenseparately at the same or at difierent speed and direction. The spinningmass winding itself helically in superimposed'layers on the mandrel orwinding rod will not be unnecessarily long retained in the spinningchamber and will under the prevailing pressure uniformly andcontinuously enter into and pass through the spinning slot.

The said and other objects of my invention will be more fully understoodfrom the following specification when read with the accompanying drawingin which several embodiments of my new device are illustrated.

In the drawing:

FIG. 1 shows a longitudinal, partly sectional view of my new extrudingnozzle attached to the outlet of an extruder;

FIGS. 2, 3 and 4 show cross sections along line AA in FIG. 1 of threedifferent embodiments;

FIG. 5 shows a longitudinal partly sectional view of still anotherembodiment comprising two individually fed inlets to the nozzle and twospinning slots;

FIGS. 6, 7 and 8 are cross sectional views on lines VIVI, VII-VII andVIII-VIII, respectively, of FIG. 5; 1

FIG. 9 shows a perspective view of an embodiment substantially identicalwith that shown in FIG. 1 however with a slightly modified mandrel orwinding rod; and

FIG. 10 shows a cross sectional view thereof taken on line XX of FIG. 9.

The same reference numerals indicate the same or equivalent elements.

The extrusion nozzle shown in FIG. 1 comprises a nozzle body 1 includinga cylindrical spinning chamber 1' and a longitudinally extendingspinning slot 4 enclosed by lips 4' which in known manner may bemutually adjustable to vary the width of said slot 4.

The spinning chamber 1' of this embodiment is open at one end and thereattached to the cylinder2 enclosing an extrusion worm 3 of an extruder.This worm 3 is rotatably driven in conventional manner and introducesIunder pressure a spinning mass into the spinning cham- Within thischamber 1 is rotatably mounted a winding rod or mandrel 5 provided witha journal 5 which rests in the end portion 1" of the body 1 and isrotatably driven by a pulley 6 or in other known manner.

However, said winding rod or bobbin 5 may be an extrusion of theextruding worm 2 or be drivingly connected therewith. It may be shapedin many different ways;' it may have a uniform circular (FIG. 2) or oval(FIG. 3)

or triangular (FIG. 4) or polygonal or any other suitable cross section,or it may have varying cross sections throughout its length as laterdescribed with reference to FIG. 5. Also, the spinning chamber 1 insteadof being cylindrical as shown in FIG. 1 may be conical as known in theart, in which case the winding rod or mandrel 1 is accordingly conicallyshaped. The surface of the winding rod or mandrel 1 may be smooth, oruniformly or partially rifled or serrated. The spinning mass enteringthe spinning chamber 1 under pressure winds itself in helical layersupon the winding rod or mandrel 1 and does not form any dead zonesretaining the mass for a dangerously long time, thus avoidingdecompositions thereof.

As shown in the drawing the winding rod or mandrel has a substantiallysized diameter compared to the diameter of the spinning chamber and thusa relatively great surface to engage the spinning mass for causing thesame to wind around in helical layers. The width of the channellongitudinally extending in the spinning chamber between the winding rodor mandrel and the inner surface of the nozzle body 1 may be made asnarrow as desired, however, it has to be wide enough not to disturb thewinding of the helical layers around the winding rod or mandrel and notto obstruct passage of the spinning mass in longitudinal direction ofspinning chamber and along the spinning slot 4. The rotational speed ofthe winding rod or mandrel may have to be changed for different spinningmasses in accordance with their specific viscosity.

If my new nozzle is used, for example, for processing polyvinylchloridethen a preferred embodiment will show a ratio of about 425275 betweenthe diameter of the cylindrical winding rod or bobbin, the diameter ofthe cylindrical spinning chamber, and the lengths of said chamber andthe substantially equally long spinning slot. The winding rod or mandrelrotates at about 30 to 40 revolutions per minute and the temperature inthe spinning chamber is held at about 200 C.

In the embodiment shown in FIG. 5, already shortly referred to above,the spinning chamber 1' within the nozzle body 1 is provided at or nearits ends with two inlet openings for feeding the spinning mass thereintoby the extrusion worms 3, 3' of extruders 2, 2', respectively, and alsowith two spinning slots 4, 4'. The winding rod or mandrel 5 showsvarying, but smoothly merging cross sections for example as shown inFIGS. 6, 7 and 8.

In most cases a winding rod or mandrel having a smooth surface will worksatisfactorily to cause the highly viscous opening mass to wind around.As stated above, the surface of the winding rod or mandrel may however,be fully or partially rifled or serrated, or it may as shown in FIGS. 9and 10 be provided with substantially radially extending projections 7,such as pins or horns or the like.

While specific embodiments of my invention have been shown and describedin detail to illustrate the application of the principles of myinvention, it will be well understood that the same may be otherwiseembodied without departing from said principles and without avoiding thescope of the appended claims.

What I claim as my invention is:

1. A spinning attachment for extruding apparatus in the manufacture ofribbons, foils, sheets or the like from heat-sensitive viscous syntheticraw material, comprising in combination a substantially cylindricalchamber open at one end to receive compressed raw material from theextruding apparatus and closed at the other end; an elongated spinningslot in said chamber extending in axial direction thereof; and a windingrod or mandrel rotatably mounted in said chamber and substantiallycoextending longitudinally therewith, said winding rod or mandrel whilerotating causing the spinning mass to wind around in helical layers andto enter the spinning slot uniformly and continuously under the pressureprevailing in the chamber.

2. A molding die attachment for extruding apparatus in the manufactureof foils or sheets from heat-sensitive viscous synthetic raw material,comprising in combination a substantially conical chamber open at itswide end to receive compressed raw material from the extruding apparatusand closed at the other end; an elongated spinning slot in said chamberextending in axial direction thereof, and a conical winding rod ormandrel rotatably mounted in said chamber and substantially coextendingtherewith, said winding rod or mandrel while rotating causing thespinning mass to wind around in helical layers and to enter the spinningslot uniformly and contiuously under the pressure prevailing in thechamber.

3. A spinning attachment according to claim 1 wherein the winding rod ormandrel has a uniform non-circular cross section.

4. A spinning attachment according to claim 2 wherein the winding rod ormandrel has a uniform non-circular cross section.

5. A spinning attachment according to claim 1 wherein the winding rod ormandrel has at least two different cross sections said cross sectionsmoothly merging one into the other.

6. A spinning attachment according to claim 2 wherein the winding rod ormandrel has at least two ditferent cross sections said cross sectionsmoothly merging one into the other.

7. A spinning attachment according to claim 1 in which the winding rodor mandrel is at least partially rifled or serrated.

8. A spinning attachment according to claim 2 in which the Winding rodor mandrel is at least partially rifled or serrated.

9. A spinning attachment according to claim 1 comprising a plurality ofprojections radially extending from said winding rod or mandrel withoutreaching the inner surface of the chamber.

10. A spinning attachment according to claim 2 comprising a plurality ofprojections radially extending from said winding rod or mandrel withoutreaching the inner surface of the chamber.

References Cited in the file of this patent UNITED STATES PATENTS2,431,274 Osborne Nov. 18, 1947 FOREIGN PATENTS 1,248,798 France Nov.14, 1960 1,052,673 Germany Mar. 12, 1959

1. A SPINNING ATTACHMENT FOR EXTRUDING APPARATUS IN THE MANUFACTURE OFRIBBONS, FOILS, SHEETS OR THE LIKE FROM HEAT-SENSITIVE VISCOUS SYNTHETICRAW MATERIAL, COMPRISING IN COMBINATION A SUBSTANTIALLY CYLINDRICALCHAMBER OPEN AT ONE END TO RECEIVE COMPRESSED RAW MATERIAL FROM THEEXTRUDING APPARATUS AND CLOSED AT THE OTHER END; AN ELONGATED SPINNINGSLOT IN SAID CHAMBER EXTENDING IN AXIAL DIRECTION THEREOF; AND A WINDINGROD OR MANDREL ROTATABLY MOUNTED IN SAID CHAMBER AND SUBSTANTIALLYCOEXTENDING LONGITUDINALLY THEREWITH, SAID WINDING ROD OR MANDREL WHILEROTATING CAUSING THE SPINNING MASS TO WIND AROUND IN HELICAL LAYERS ANDTO ENTER THE SPINNING SLOT UNIFORMLY AND CONTINUOUSLY UNDER THE PRESSUREPREVALILING IN THE CHAMBER.